CUPERTINO, Calif. - Apple shares are continuing their downward trajectory despite what some could interpret as a positive for the company, the return of Google Maps to the iPhone.

Shares in the Cupertino, Calif., tech giant (AAPL:Nasdaq) were down 3.68 per cent to $510.25 Friday on heavy volume of 23.6 million shares on the Nasdaq.

Apple stock had been trading above $700 as recently as late September.

The world's most popular online mapping system returned to iPhone late Wednesday with the release of the Google Maps iPhone app.

The release comes nearly three months after Apple Inc. replaced Google Maps as the device's built-in navigation system and inserted its own map software into the latest version of its mobile operating system.

Apple's maps application proved to be far inferior to Google's, turning what was supposed to be a setback for Google into a vindication.

The product's shoddiness prompted Apple CEO Tim Cook to issue a rare public apology and recommend that iPhone owners consider using Google maps through a mobile Web browser or seek other alternatives until his company could fix the problems.

Cook also replaced Scott Forstall, the executive in charge of Apple's mobile operating system, after the company's maps app became the subject of widespread ridicule.

In one example brought to light this week, Australian police derided Apple's maps as "life-threatening" because the system steered people looking for the city of Mildura into a sweltering, remote desert 44 miles from their desired destination.

Digital maps are key battleground in mobile computing because they get used frequently on smartphones and can pinpoint a user's whereabouts.